As early as the 1950s the seemingly invincible tobacco companies felt the strain of mounting anti-smoking pressure and locked arms to blunt critics, hundreds of private industry documents made public Thursday reveal.

The 847 documents show an industry under siege that turned to a core group of lawyers to coordinate a multi-layered defense relying on science, public relations and political muscle.

In 1967 tobacco industry officials concluded that an industry-funded researcher had “outlived his usefulness as (an) investigator” after his experiments produced lung cancer in mice.

That same year the industry considered using the popular “Monkees” singing group as part of a “youth heroes” campaign.

And in 1970, one researcher wrote in a memo to the head of Philip Morris, “Let’s face it. We are interested in evidence which we believe denies the allegations that cigarette smoking causes disease.”

While the legal value of the documents is unclear, they are certain to become a powerful force early next year when Congress begins debating a proposed tobacco settlement that would protect tobacco companies from potentially crippling lawsuits in return for paying $368.5 billion over 25 years in compensation for damages.

The picture they paint is of a tobacco defense effort that was costly and far-reaching, subtle and direct.

The cache of documents were released on the Internet by one of tobacco’s staunchest allies, Rep. Thomas Bliley, R-Va., over the strong objections from the companies, Brown & Williamson, Philip Morris Inc., R.J. Reynolds Tobacco Co., and the Lorillard Tobacco. Bliley is head of the House Commerce Committee which will play a key role in shaping any tobacco legislation.

He subpoenaed the documents after the companies failed to turn them over voluntarily. Bliley said Congress needs to see the documents before taking any action on a proposed settlement. And, he said, the public has a right to the information.

“The tobacco firms are asking for unprecedented legal immunity, but first they need to own up to their past,” Sen. Patrick Leahy, D-Vt., who has been pressing for the release of more private industry documents.

In a statement the four companies declined to comment on the documents because they believe the information is protected by attorney-client privilege. But the companies downplayed their importance.

“We must learn from, but not be obsessed by, events past and recognize the value of a comprehensive national policy and the promise it holds for the future,” it said.

There did not appear to be a single, incriminating document but, taken together, the papers provide new insight to the lengths tobacco companies went to protect their business.

The documents also showed how the industry tried to shape public opinion about smoking. In a 1982 memo, industry officials discussed a script for an up-coming film on smoking and lung cancer. The script tried to reinforce doubts about the health hazards of smoking, opening with a discussion about how science has answered difficult questions over time.

But, the narrator says, “Perhaps the biggest tragedy of all is when an important medical question has not been answered, but almost everyone thinks it has. That’s a tragedy of a different sort.”

The industry’s far-flung efforts had origins in 1955 when the Federal Trade Commission regulators imposed more stringent guidelines on tobacco advertising. The consequences of that decision were quickly clear to the tobacco companies, the documents show.

By 1958, the four major tobacco companies, along with their lawyers, had agreed to obtain and share “cancer literature which would be helpful to counsel for all companies defending claims against them.”

But the documents, and related papers released this week in a Minnesota court, also show cracks in the industry’s united front.

In 1982, the industry’s political arm, the Washington-based Tobacco Institute, begged sponsors for more money. The Institute claimed that its political action committee was “chronically underfunded,” according to a May 20 memo.

Foreshadowing hard times ahead in Washington, that memo also outlined a strategy to increase the industry’s influence at the state level.

Strong state programs would “enhance our federal programs by supporting state level friends who could be called upon to assist with their congressmen and senators in Washington,” the paper said.

And despite the subdued legal language in the documents, the industry’ sometime showed its distaste for its critics.

A 1979 memo from the Liggett Company’s general counsel, Joseph Greer, suggested a way to respond to outspoken criticism from the Health Education and Welfare Secretary Joseph Califano.

“Attached is a new draft of the Institute’s reply to the Ayatollah Califano,” Greer’s memo began.